ANDROID: scsi: ufs: Make CONFIG_SCSI_UFS_HPB compatible with the GKI

Move the ufshpb_dev member into a new structure such that enabling HPB
does not affect the layout of other members of struct ufs_hba. This change
does not affect the ABI since UFS HPB support is currently disabled.

The only function that allocates a struct ufs_hba instance is
ufshcd_alloc_host() and that function allocates struct ufs_hba dynamically.
Modify that function such that it also allocates memory for the HPB data if
necessary.

Bug: 194163838
Bug: 195507090
Test: Built the kernel with this patch applied and installed it on an Android device.
Change-Id: Ia4c5ba07ae343576373ec116553c5fdee8f75a94
Signed-off-by: Bart Van Assche <bvanassche@google.com>